Hi Julien, > On 17 Mar 2021, at 11:20, Julien Grall <jul...@xen.org> wrote: > > > > On 16/03/2021 17:16, Bertrand Marquis wrote: >> Hi Julien, > > Hi Bertrand, > >>> On 16 Mar 2021, at 15:27, Julien Grall <jul...@xen.org> wrote: >>> >>> >>> >>> On 15/03/2021 13:32, Bertrand Marquis wrote: >>>> Hi Julien, >>> >>> Hi Bertrand, >>> >>>>> On 13 Mar 2021, at 16:06, Julien Grall <jul...@xen.org> wrote: >>>>> >>>>> From: Julien Grall <jgr...@amazon.com> >>>>> >>>>> Hi all, >>>>> >>>>> Last year, Arm released a whitepaper about a new category of speculation. >>>>> (see [1] and [2]). In short, a processor may be able to speculate past >>>>> some of the unconditional control flow instructions (e.g eret, smc, br). >>>>> >>>>> In some of the cases, the registers will contain values controlled by >>>>> the guest. While there is no known gadget afterwards, we still want to >>>>> prevent any leakage in the future. >>>>> >>>>> The mitigation is planned in two parts: >>>>> 1) Arm provided patches for both GCC and LLVM to add speculation barrier >>>>> and remove problematic code sequence. >>>>> 2) Inspection of assembly code and call to higher level (e.g smc in our >>>>> case). >>>>> >>>>> I still haven't looked at 1) and how to mitigate properly Arm32 (see >>>>> patch #1) and SMC call. So this issue is not fully addressed. >>>>> >>>>> Note that the ERET instruction was already addressed as part of XSA-312. >>>> On my tests, this serie is breaking the arm64 build: >>>> | aarch64-poky-linux-ld >>>> --sysroot=/home/bermar01/Development/xen-dev/build/profile-fvp-base.prj/tmp/work/fvp_base-poky-linux/xen/4.15+git1-r0/recipe-sysroot >>>> -EL --fix-cortex-a53-843419 --fix-cortex-a53-843419 -r -o >>>> built_in.o memcpy.o memcmp.o memmove.o memset.o memchr.o clear_page.o >>>> bitops.o find_next_bit.o strchr.o strcmp.o strlen.o strncmp.o strnlen.o >>>> strrchr.o >>> >>> I can't see any build failure with the following GCC: >>> >>> 42sh> aarch64-linux-gnu-gcc >>> aarch64-linux-gnu-gcc (Ubuntu/Linaro 7.5.0-3ubuntu1~18.04) 7.5.0 >>> Copyright (C) 2017 Free Software Foundation, Inc. >>> This is free software; see the source for copying conditions. There is NO >>> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. >>> >>> AFAICT, there is also no compilation issue reported by gitlab: >>> >>> https://gitlab.com/xen-project/patchew/xen/-/pipelines/269989894 >>> >>> What's the version of your compiler? Do you have steps to reproduce your >>> setup? >> You need to have earlyprintk enabled >> I am using gcc 7.5.0: >> aarch64-linux-gnu-gcc (Ubuntu/Linaro 7.5.0-3ubuntu1~18.04) 7.5.0 >> one configuration triggering the issue is using the default .config with the >> following items added: >> CONFIG_SUPPRESS_DUPLICATE_SYMBOL_WARNINGS=y >> CONFIG_DEBUG_LOCK_PROFILE=y >> CONFIG_PERF_COUNTERS=y >> CONFIG_PERF_ARRAYS=y >> CONFIG_DEVICE_TREE_DEBUG=y >> CONFIG_DEBUG_TRACE=y >> CONFIG_EARLY_PRINTK_JUNO=y >> CONFIG_EARLY_UART_PL011=y >> CONFIG_EARLY_PRINTK=y >> CONFIG_EARLY_UART_BASE_ADDRESS=0x7ff80000 >> CONFIG_EARLY_UART_PL011_BAUD_RATE=115200 >> CONFIG_EARLY_UART_INIT=y >> CONFIG_EARLY_PRINTK_INC="debug-pl011.inc” > > Thanks for providing the .config. I managed to reproduce it. So I removed > "asm_defns.h" everywhere but forgot to include it in the "config.h" :/. > > This small change fixed the error: > > diff --git a/xen/include/asm-arm/config.h b/xen/include/asm-arm/config.h > index 51273b9db1fc..c7b77912013e 100644 > --- a/xen/include/asm-arm/config.h > +++ b/xen/include/asm-arm/config.h > @@ -192,7 +192,7 @@ extern unsigned long frametable_virt_end; > #define watchdog_enable() ((void)0) > > #if defined(__ASSEMBLY__) && !defined(__LINKER__) > -#include <asm/asm-offsets.h> > +#include <asm/asm_defns.h> > #include <asm/macros.h> > #endif > > Would you still be happy to review the series before I send a v3?
Sure, I will restart my tests with this change now and review the v2 once passed. Cheers Bertrand > > Cheers, > > -- > Julien Grall
